Abstract There is an advantage in the recognition of happy faces, such that happy facial expressions are identified more accurately and quickly than other types of facial expressions. This phenomenon has been found in a large number of studies utilizing either expression categorization tasks or visual search tasks, in which schematic faces and facial expressions were used as stimuli. There are three theoretical explanations for this advantage: the diagnostic value hypothesis, affective uniqueness hypothesis and frequency of occurrence hypothesis. In recent years, event-related-potential (ERP) studies have found that this advantage is formed in the response selection stage of the recognition process, but it remains unclear when this advantage initially emerges. Future studies using functional magnetic resonance imaging (fMRI) methods are necessary to investigate the cognitive neural mechanism of this advantage in recognition of happy faces.